Well, it is another "art" that you need to learn. I have pieces from $5 up to about $200. All of my pieces are intended to be used daily. There is no exact formula. I would say that I sell as many big bowls dollar wise as I do smaller pieces. The marked for big pieces, and to me that is over 14 inches is limited. I never did well at the fancy shows in part because I don't do fancy like carving or painting or texturing. I used to make furniture for sale, solid wood, and people would expect Ikea prices for solid wood furniture. I am a terrible salesman though.
robo hippy